4. DeNOx catalysis

4.1 Introduction

Catalytic elimination of the nitrogen oxides emitted by diesel and lean-burn gasoline engines is a regulatory requirement, particularly in the USA from 2010 and in Europe from 2014. It represents a real technical challenge for researchers, since the richness window of these engines is unfavorable to NOx reduction reactions (the environment being highly oxidizing overall) (figure 27 ).

The regulatory aspect is not the only one to be taken into account in the NOx reduction strategy. At the same time, targets for reducing...